1. Field of the Invention
The invention relates to an optical image stabilizer, and more particularly to the stabilizer that is able to improve and/or compensate kinetic deviations of the lens module while in focusing or zooming.
2. Description of the Prior Art
Digital photography technology has been widely applied to most of the portable electronic devices such as the cellular phones. Various miniaturized techniques in the lens module are involved to make all these applications possible; in particular, the voice coil motor (VCM) technique. The VCM introduces a combination of coiled magnets and spring plates to drive a lens to move back and forth along a photo axis for image-capturing, so as to perform auto-zooming and/or auto-focusing of the lens module. Further, in this trend of devices capable of high-level photographing functions, photographic quality and various camera functions are also demanded; such as thousand pixels, anti-hand shake ability and so on.
In an optical system composed of a lens module and an image-compensation module, such as a camera system or a video recorder system, hand shake or some external situations usually occur to bias the optical path so as to degrade the imaging upon the image-compensation module and further to obscure the formation of the images. A conventional resort to resolve this problem is to introduce a further compensation mechanism for overcoming possible shaking during the imaging. Such a compensation mechanism can be either digital or optical.
In the art, the digital compensation mechanism is to analyze and process the digital imaging data capturing by the image-compensation module, so as to obtain a clearer digital image. Such a mechanism is also usually called as a digital anti-shake mechanism. On the other hand, the optical compensation mechanism, usually called as an optical anti-shake mechanism, is to add a shake-compensation module upon the lens module or the image-compensation module. Currently, most of the optical anti-shake mechanisms in the market are consisted of plenty complicated or cumbersome components and thus are usually complicatedly structured, difficulty assembled, expensive, and hard to be further miniaturized. Obviously, a further improvement upon such the anti-shake mechanism is definitely necessary.
Referring to FIG. 1, an optical compensation mechanism in accordance with the Japan Patent No. 2002-207148 is schematically shown. The optical compensation mechanism includes four flexible steel strings 400k-403k to sustain a lens unit 203k upon a circuit board 301k having a central image sensor 300k. The lens unit 203k further includes a lens 200k and a lens holder 202k. The lens unit 203k can be a zooming or a focusing lens module. The lens 200k centrally located in the lens unit 203k can move back and forth with respect to the lens holder 202k along an optical axis 201k. While in meeting a shake, a relative displacement between the lens unit 203k and the circuit board 301k would be generated. Then, through two relative displacement sensors 500k, 501k and a position sensor 503k, both the X-axial displacement and the Y-axial displacement between the lens unit 203k and the circuit board 301k can be transmitted to an anti-shake unit 504k. According to the axial displacements, the anti-shake unit 504k controls and drives a shift unit 502k to perform a corresponding compensation movement upon the lens unit 203k with respect to the circuit board 301k, such that obscure imaging due to the shake can be avoided in the image sensor 300k. 
Nevertheless, the aforesaid Japanese patent No. 2002-207148 is not only aiming at obscure imaging by hand-shaking, but also affecting the volume of apparatus mainly by the combination of the anti-shake unit 504k and the shift unit 502k. As a result, the X-Y surface parallel to the lens unit 203k cannot be further reduced. Contrarily, the present invention herein is to thoroughly utilize the reduced-space concept to invent an optical image stabilizer to restrain X-axial and Y-axial deviations contributed by handshakes, and to reduce further apparatus's X-Y surface (so as to reduce as well the apparatus's volume). Thereby, parts for the imaging apparatus can be achieved at a state of lightweight, slimness, shortness and miniaturized in various manifolds.